Bloomberg News

U.S. Drought Monitor Report for the Week Ending March 5 (Text)

March 07, 2013

Following is the text of the weekly U.S. Drought Monitor as released by the National Drought Mitigation Center in Lincoln, Nebraska:


Weather Summary: The past week featured generally dry conditions
across most of the western half of the contiguous 48 states with
a deep trough over the eastern half.  The deep low-pressure
system over the eastern half of the contiguous 48 states yielded
widespread precipitation, with rainfall totals generally less
than 3.0 inches from the Ohio Valley to the Northeast, and
across portions of the Mid-Atlantic.  The Pacific Northwest was
another stormy region, with multiple reports of more than 4
inches of precipitation during the past week.  Isolated reports
of 0.5-1.5 inches of precipitation came in from stations across
the Central Rockies.  Elsewhere, precipitation amounts were less
than 0.5 inch.

The Northeast and Mid-Atlantic: Generally 0.5 to locally 1.5
inches fell on the D0 areas, but the precipitation was not
enough to change the intensity or coverage of the dry areas
substantially.  Moderate rains (0.5-1.5 inches) fell across
central Virginia, prompting some trimming of the D0 (abnormal
dryness) in this region.

The Southeast: Light to moderate rains (0.5 - 1.8 inches) fell
across the Carolinas.  No change was made to the depiction
across North Carolina as below-normal streamflow conditions were
reported by the United States Geological Survey (USGS) across
the central Piedmont and Sand Hills region, where streamflows
are currently depicted in the “less than 10th percentile” range.
Recent rains were heavier across Georgia and South Carolina,
ameliorating some impacts and long-term deficits, so a 1-
category improvement was indicated from counties near the
Georgia-South Carolina border and across southern Georgia.

D0 was scaled back across northern Florida, which benefitted
from recent rains (60- and 90-day Percent of Normal
Precipitation values all greater than 100), especially during
the most recent 30 days (Percent of Normal Precipitation values
of 200 percent or higher).  In contrast to the wetter conditions
across north Florida, dry conditions persisted south of a line
from Daytona to Ocala, resulting in the expansion of severe
drought (D2) across east central Florida.  Several brushfires
have been reported in Marion and Volusia Counties.  Since
November 1, 2012, Daytona Beach (Volusia County) has received
4.64 inches of rain, or just over 40 percent of the normal of
10.5 inches, ranking as the 7th driest period in 80 years, just
crossing the D2 threshold. Similarly, since November 1 of last
year, Ocala (Marion County) has received 5.4 inches, or just
over 40 percent of the normal of 11.5 inches.  That ranks as the
11th driest such period in 120 years, which also fits the D2
criteria. Also, D0 (abnormal dryness) was expanded across most
of central Florida as dry conditions have persisted, tempered by
the fact that this is the climatological dry season for most of
Florida.

The Midwest: Moderate precipitation (0.5 - 1.5 inches) fell
across parts of Missouri and southern Illinois.  Missouri Dept.
of Conservation personnel at Busch Wildlife (western St. Charles
County) reported that ponds and lakes have recovered nicely,
adding about 18 inches during the past few weeks.  These lakes
had been between 2.5-3.0 feet below normal at their lowest point
of this drought, and as of a few weeks ago were only 4 inches
above that low point, now only about 1 foot below normal. Other
ponds in Pike County, Missouri have not recovered as much, as
there is still significant snow and ice pack that has not
melted.  Snow Water Equivalent (SWE) of the snowpack is in the
2-3 inch range, so warmer temperatures should yield considerable
benefit to well depths and pond/lake levels in the days and
weeks ahead through melting.

Significant precipitation has fallen across Minnesota and
Wisconsin during the past 90 days, but most of it is sitting on
top of the frozen ground, locked away in the snowpack.  The
scenario is the same across much of northeast Iowa, so no
changes were made across the entire region.

The Great Plains: Most of the changes to the southern Great
Plains were increased in the drought coverage and intensity
across Texas.  The Office of the State Climatologist for Texas
reported that February as a whole was largely drier than
January, and evidence of this can be seen as the 2 and 6-month
SPI blend time scales tend toward drier values. The reservoir
situation continues to be poor--while the eastern half of the
state is comparatively well-off, west Texas continues to suffer,
contributing to the persisting record-low reservoir conservation
storage.  Southern Texas was especially dry, with single digit
relative humidity values and high winds prompting an expansion
of all drought categories across this region.

The lone area of improvement (reducing the intensity of drought)
was made to the Panhandle of Oklahoma.  Precipitation has been
above normal for the past 30 and 60 days, with a significant
rain event last week.  Minimal improvement was measured in local
soil moisture, so D3 (extreme drought) was retained for Cimarron
County.

The Rockies: Winter storms have brought some precipitation to
portions of the Central and Northern Rockies, largely missing
the southern Rockies since the start of the year.  An area of D3
conditions was removed from Northwest Colorado based on
standardized precipitation indices (SPIs) derived from PRISM
gridded data (since this is a very data sparse region).  The
rest of the D3 region was retained as SNOTEL precipitation
percentiles are primarily ranked below the 5th percentile.
Across northeastern Colorado, D4 (exception drought) was
trimmed, based on recent (past 30 days) precipitation amounts
being above normal.

Some of the storms that brought heavy rains to the Pacific
Northwest also provided precipitation to the interior portions
of the Northern Rockies.  Some improvements were made to
southern Idaho and northern Utah, based on a reassessment and
using SPI3, SPI6, and a trailing, weighted SPI index as guiding
values.

Hawaii, Alaska, and Puerto Rico: Heavy precipitation fell across
many parts of the Alaskan Panhandle, so the area of D0 was
trimmed out.  Dry conditions persisted across interior Alaska,
but no change was made as enough precipitation was recorded to
stay the degradation.

Precipitation deficits continued across Puerto Rico, including
the high terrain.  D0 (abnormal dryness) was introduced over
much of the Island, along the central high lands and over
southeastern portions, to reflect the below normal precipitation
amounts during the past 60-days.

Looking Ahead:  During the next 5 days (March 7-11, 2013),
moderate to heavy precipitation is forecast from the lower
Mississippi Valley to the Mid-West, and across portions of the
Central and Southern Rockies.  Additional precipitation is
likely for the northeast (early in the period) and the Pacific
Northwest (episodically during the entire period. Beyond that
timeframe, drier than median conditions are favored across the
southern tier of the CONUS and southern Alaska, as the main
storm track is forecast along the U.S.-Canada border.

To contact the reporter on this story: Stephen Rose in Washington at srose31@bloomberg.net

To contact the editor responsible for this story: Marco Babic at mbabic@bloomberg.net


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